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I've been using MP3 for a decade for my audio collection, but with the (not so) recent developments in open source vs patented codecs such as H.264 I am wondering if an alternative format is warranted.

I'm slightly familiar with OGG and FLAC as other options, but am unsure if I should begin re-ripping audio CD's to one or neither.

Can anyone provide a guide as to what the pros and cons of these formats are with respect to:

  • Audio quality/loss
  • Licensing and patent issues, if any
  • Performance

I am not asking about support by major media vendors such as Apple and Amazon. I am only concerned with ripping my existing audio CD's without causing major headaches in the future with respect to audio quality ("Damn, I wish I'd known to disable joint stereo back then!") and legal issues ("I can't copy these XYZ files to the new ACME Player™ because it's hindered by legal ramifications?").

Further, while I want to re-rip some music to MP3 due to quality issues, is there any reason I should not stick to MP3? Perhaps jumping to a new format is not warranted.

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Actually, I am wondering if this is on-topic... I don't think it actually as, at least not the way it's phrased: ripping the CD collection is not on-topic. Storing recorded audio, OTOH, probably would be on-topic. Can't vote for closing, though, and probably wouldn't. –  Jürgen A. Erhard Jan 14 '11 at 21:29

1 Answer 1

up vote 8 down vote accepted

Audio quality/loss

FLAC is, by definition, loss-less. From a FLAC file you can recreate the original PCM stream, bit-for-bit.

Vorbis (sometimes referred to as just Ogg when you know the codec is for audio-only), the scheme used in the Ogg container to do the compression, is a lossy compressor, same as MP3. From an Ogg Vorbis encoded file you cannot recover the original WAV stream, bit-for-bit, but on playback the claim is it sounds pretty much the same.

My opinion: for long term storage you want lossless compression using a codec with a strong developer backing. FLAC definitely meets that standard. Using a lossless compression scheme means you save storage space, but you can transcode to any future format and know that you're re-encoding an exact copy of your source as it was when it was first ripped. I personally rip my CDs to FLAC and transcode to m4a for use on my iPhone.

Licensing and patent issues, if any

Both FLAC and Ogg Vorbis are patent-free. Both are in the public domain. Both are completely free to use in commercial and non-commercial products.

If you use source code supplied by Vorbis or the FLAC developers it comes with a GPL license. But you can code your own implementation of the specs and not have to release your source code, the spec itself is public domain.

My opinion: both are formats with lots of developer backing and both specs are in the public domain meaning even if all the current developers disappear, if the code gets lost, someone with enough drive can always build a codec from the raw spec at any point in the future if they need it. That's good future-proof-ness that is. There are also GPL implementations currently available so there is code that will remain in the public domain for all time to come, assuming it's never lost, you can always get the codec back.

Performance

Decoding FLAC is not very CPU intensive. Akin to uncompressing some data. Vorbis decoding is more intensive due to its lossy nature and the algorithms required to recreate the sound are more involved. But on modern hardware neither format will push the limits of your processing power.

My opinion: I'd say performance is a non-issue when comparing the formats.

is there any reason I should not stick to MP3?

This is somewhat subjective. If your MP3s sound good and you don't mind using a format that's patented and not free to implement than no, there's no good reason to switch. But for archival of data I'm of the mind that non-proprietary compression for space saving coupled with public domain algorithms are the only way to protect yourself from the Beta Syndrome (where you end up with a bunch of stuff on media that can only be played on proprietary gear that is no longer made by the one company that made the stuff to begin with). FLAC is that codec. Ogg Vorbis is a nice alternative to MP3 but lossy codecs, IMO, have no place in long term archival. A rip to FLAC and then a transcode to the flavour-of-the-week lossy codec for use on your cellphone is the best strategy around. Go forth and FLAC my good man.

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+1 Good detail. –  Matthew Read Jan 13 '11 at 22:23
    
@Ian C, thank you for a great answer, I appreciate the insight! –  JYelton Jan 13 '11 at 22:30
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Correction #1: the actual encoding/decoding code for FLAC and Vorbis is under a BSD license, so you can even use it in close-source software. The utilities are GPL'ed. –  Jürgen A. Erhard Jan 14 '11 at 20:35
1  
Correction #2: even if the code for the en/decoder were under GPL, if all the devs were to disappear, it would still be under GPL, so no need to rewrite it from spec. Rewrite from spec is only needed if you cannot for whatever reason use the BSD'd ref implementation. There was/is (not sure) a fixed-point Vorbis decoder some company wrote, that's one example for a reimplementation from the spec. –  Jürgen A. Erhard Jan 14 '11 at 20:38
    
Other than that, +1 for a very good and thorough answer :D –  Jürgen A. Erhard Jan 14 '11 at 20:38

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